Pretty early on I found +1 identity gloves and a +1 identity ring. I found that useful enough to avoid wasting skill points. Considering how easy it is to make money in this game, at 100-250 gp for merchants to identify, I'd save my skill points. (also, the teleporter stones make getting to the merchants quite easy.)

As for the last part of the catacombs, playing a warrior I found very difficult. What was key to getting through was investing 1 point in Meteor Storm (I think it's called)… my God, what a difference that made! It all depends if you want to stick to pure warrior or go battle mage.